Beginning yesterday afternoon at 3:37 PM AKST, tremor amplitude increased sharply and remained elevated for approximately one hour. At 4:14 PM AKST, the tremor amplitude briefly matched the highest amplitude seen during the current episode of unrest. This tremor was strong enough to be recorded on all seismic stations on Redoubt Volcano as well as many stations surrounding Cook Inlet. Since that time, tremor amplitude has decreased significantly. Last night around 10:40 PM AKST, the number of discrete earthquakes increased and remained elevated until about 2:55 AM AKST today. Preliminary analysis of these earthquakes indicate they are occurring at shallow depth (1 to 3 km) below the summit crater of Redoubt. Since that time, discrete events are continuing at a lower rate, and tremor levels remain low. These variations in the character of seismic activity indicate that conditions have changed at shallow depths beneath the volcano. AVO is currently analyzing this seismic activity and will issue further information as it becomes available.

An observation flight to the volcano is currently underway. Winds are too high at the volcano to perform gas measurements today.

A small steam plume is visible in clear HutCam images today.

AVO continues to monitor Redoubt Volcano closely, and the observatory is staffed 24 hours a day.

AVO has received no reports of activity at Cleveland in the past 24 hours, and nothing unusual has been seen in partly cloudy satellite images over the same timeframe. Low-level ash emissions may occur with little or no warning.

The Alaska Volcano Observatory is a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys.

VOLCANO ALERT LEVELS

NORMALVolcano is in typical background, noneruptive state or, after a change from a higher level, volcanic activity has ceased and volcano has returned to noneruptive background state.

ADVISORYVolcano is exhibiting signs of elevated unrest above known background level or, after a change from a higher level, volcanic activity has decreased significantly but continues to be closely monitored for possible renewed increase.

WATCHVolcano is exhibiting heightened or escalating unrest with increased potential of eruption, timeframe uncertain, OR eruption is underway but poses limited hazards.

WARNINGHazardous eruption is imminent, underway, or suspected.

AVIATION COLOR CODES

GREENVolcano is in typical background, noneruptive state or, after a change from a higher level, volcanic activity has ceased and volcano has returned to noneruptive background state.

YELLOWVolcano is exhibiting signs of elevated unrest above known background level or, after a change from a higher level, volcanic activity has decreased significantly but continues to be closely monitored for possible renewed increase.

ORANGEVolcano is exhibiting heightened or escalating unrest with increased potential of eruption, timeframe uncertain, OR eruption is underway with no or minor volcanic-ash emissions [ash-plume height specified, if possible].

REDEruption is imminent with significant emission of volcanic ash into the atmosphere likely OR eruption is underway or suspected with significant emission of volcanic ash into the atmosphere [ash-plume height specified, if possible].